Sieve for a thresher, especially a combine-harvester for harvesting grains

Abstract

A combine-harvester for harvesting grains has a zigzag arrangement and is formed from repeating portions ( 13, 13 a , 13 b , 13 c ) which each portion includes a profile ( 14, 14 a , 14 b , 14 c ). Each profile has a first leg ( 16 ), which is arranged at an angle to a second leg ( 18 ). The first leg ( 16 ) is provided with an extension ( 22 ). The extension is arranged parallel to the first leg ( 16 ) in a transverse direction to the conveying direction ( 6 ) and ends at an edge. The extension ( 22 ) projects in conveying direction ( 6 ) beyond the connection area ( 19 ) of the first leg ( 16 ) with the second leg ( 18 ). The extension is arranged ahead of the second leg ( 18 ) in the conveying direction ( 6 ). Stems ( 27 ), which possibly fall onto the sieve surface, are carried by the extensions ( 22 ). As a result of the movement of the sieve as it is moved in the conveying direction ( 6 ), the stems fall off the sieve surface ( 5 ).

What is claimed is:  
     
       1. A sieve for a thresher comprising: 
       a sieve surface running parallel to a conveying direction, when seen in a section, includes a base-profile with a zigzag configuration, said base is built up from repeated consecutive portions with each portion including a first leg and a second leg, said first and second legs in the said section enclose an angle between each other, said first leg being arranged ahead of said second leg in the conveying direction enclosing a first angle with a first imaginative plane, said first angle is smaller than a second angle, which is formed between the second leg and the first plane, and said first and second legs form a connection area transverse to the conveying direction and openings being distributed in the second leg, and said first leg including an extension which continuously runs along the first leg and ends in an edge, said edge projects in conveying direction beyond said connection area between the first leg and the second leg towards a portion, which is arranged ahead in the conveying direction.  
     
     
       2. The sieve according to  claim 1 , wherein the extension is arranged in a plane with the first leg. 
     
     
       3. The sieve according to  claim 1 , wherein the extension is formed integrally with the first leg. 
     
     
       4. The sieve according to  claim 1 , wherein the edge of the extension reaches at the most to a second imaginative plane, said second plane being arranged at a right angle to the first plane and contains the connection area between said first leg and second leg, which belong to a portion, which in the conveying direction is arranged ahead of a second portion, whose first leg has the extension. 
     
     
       5. The sieve according to  claim 1 , wherein the sieve surface is constructed from profiles running transversely to the conveying direction and each profile corresponds, respectively, to a portion, each profile having a connection leg, which seen in a section parallel to the conveying direction projects from the end of the second leg to the first leg in an opposite direction and is arranged parallel to the first leg. 
     
     
       6. The sieve according to  claim 4 , wherein the profiles are made from sheet metal by bending said sheet metal. 
     
     
       7. The sieve according to  claim 4 , wherein the profiles are formed from casting profiles made from aluminum or plastic material or said profiles are formed completely as a sieve from molded aluminum or plastic material. 
     
     
       8. The sieve according to  claim 1 , wherein the edge of the extension is serrated. 
     
     
       9. The sieve according to  claim 1 , wherein the edge is sharp-edged.